/* 全局样式重置与基础设置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: "Arial", "微软雅黑", sans-serif;
}

body {
    background-color: #fdf5e6; /* 米黄色背景，模拟手写纸 */
    padding: 20px;
    line-height: 1.8;
}

header {
    text-align: center;
    margin-bottom: 30px;
}

header h1 {
    font-size: 28px;
    color: #333;
}

nav {
    display: flex;
    justify-content: space-around;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.nav-btn {
    padding: 10px 15px;
    background-color: #fff;
    border: 1px solid #ccc;
    border-radius: 5px;
    cursor: pointer;
    transition: all 0.3s;
}

.nav-btn.active {
    background-color: #ffd700;
    border-color: #ffd700;
    font-weight: bold;
}

.module {
    display: none;
    background-color: #fff;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    margin-bottom: 20px;
}

.module.active {
    display: block;
}

.module h2 {
    color: #ff4500; /* 红色标题，匹配手写风格 */
    margin-bottom: 15px;
}

.sub-module {
    margin-bottom: 20px;
    padding-left: 10px;
    border-left: 2px solid #ff4500;
}

.sub-module h3 {
    color: #ffa500; /* 橙色子标题 */
    margin-bottom: 10px;
}

ul {
    margin-left: 20px;
}

input, textarea, select {
    width: 100%;
    padding: 8px;
    margin: 5px 0;
    border: 1px solid #ccc;
    border-radius: 4px;
}

button {
    padding: 10px 20px;
    background-color: #4caf50;
    color: #fff;
    border: none;
    border-radius: 4px;
    cursor: pointer;
}

button:hover {
    background-color: #45a049;
}

#submit-feedback {
    color: #f44336;
    font-weight: bold;
}